<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>字体</title>
    <style>
        .c1{
            font-size: 20px;
            font-weight: 100;
            font-family: '宋体';
        }
        /*
            1.5em = 1.5*父元素字体大小
            即:1.5*20px = 30px
         */
        .c2{
            font-size: 1.5em;
            font-weight: 400;
            font-family: '楷体';
        }
        .c3{
            font-size: 30px;
            /*font-weight: 700;*/
            font-weight: bold;
        }
        /*
            浏览器默认字体大小:16px
         */
        .c4{
            font-size: 16px;
            font-weight: bolder;
        }
        #p1{
            font-family: '宋体';
            font-style: italic;
        }
        #p2{
            font-family: '楷体';
            font-style: oblique;
        }
        #p3{
            font-family: 'Courier New';
        }
        #p4{
            font: italic bolder 20px '宋体';
        }
    </style>
</head>
<body>
<div class="c1">这是c1的div
<div class="c2">这是c1中的div</div>
</div>
<div class="c3">这是div</div>
<div class="c4">这是div</div>
<div class="c5">这是div</div>
<hr>
<p id="p1">第1个段落</p>
<p id="p2">第2个段落</p>
<p id="p3">第3个段落</p>
<p id="p4">第4个段落</p>
</body>
</html>